Method of correcting printing plates and printing plates produced thereby



Aug. 11, 1%25.

L W. CLAYBOURN METHOD OF CORRECTING PRINTING PLALES AND PRINTING PLATES PRODUCED THEREBY Filed March 19, 1921 9 Sheets-Sheet 1 Aug. 11., was. 1,5493% L. W. CLAYBOURN METHOD OF CORRECTING PRINTING PLATES AND PRINTING PLATES PRODUCED THEREBY Filed March 19, 1921 9 Sheets-Sheet 5 i ignfi .EJCQ Z EIEEEEEGE ZEEEEE 0 @@EEE@ I \f k @UUUUUUW .UUUUUUUPW 7 L. W. CLAYBOURN METHOD OF CORRECTING PRINTING PLATES AND PRINTING PLATES PRODUCED THBREBY Filed March l9, 1921 9 Sheets-Sheet 4 U -1 AM. M v

Aug. H, 3925. 1,549,185

L w. CLAYBOURN METHOD OF CORRECTING PRINTING PLATES AND PRINTING PLATES PRODUCED THEREBY Filed March 19, 1921. 9 Sheets$heet 5 u hwgzgwg pMMfg L. W. CLAYBOURN METHOD OF CORRECTING PRZNTING PLATES AND PRINTING PLATES PRODUCED THBREBY Fil d Mar h 1 1921 Sheets-Sheet b r 2'42 jlmzfi 1 15 19 373;? 13f; 1319 2 My Aug. 11, 1925. 1,549,185

' L. W. CLAYBOURN METHOD OF CORRECTING PRINTING PLATES AND PRINTING PLATES PRODUCED THBREBY Filed March 19, 1921 9 Sheets-Sheet v L. W. CLAYEZOURN METHOD OF CORRECTING PRINTING PLATES AND PRINTING HATES PRODUCED THEREBY 1921. 9 Sheets-Sheet 8 Filed March Avg. H, 3% r C 1. W. CLAYEQURN METHOD OF CORRECTING PRINTING PLATES AND PRINTING PLATES PRODUCED. THEREBY il Mar h 19 1921 9 Sheets--$heet 9 a m w Patented Aug. lil, i925.

LESLIE W. CLAYBOUEN, 0F MENASHA, WISCONSIN.

METHOD on CORRECTING rnlu'rrno rLArns Ann 'rnrnrino rrirrns rnonooten trisnnnnzt.

Application filed March 19, 1921. Serial No. 453,665.

1 0 You ril /10m it may concern:

Be it known that. LlinsnrnlV. CLAYBOURN, n citizen of the United States, residing at Menasha, in the county of Winnebago and State of Wisconsin, have invented certain new and useful Improvements in Methods of Correcting Printing Plates and Printing Plates Produced Thereby, of which the following-is a specification.

it is the objectot my invention to provide a new and improved method of correcting printing plates, whereby to minimize or substantially reduce so-ealled IDZLkQ'lQAdY on the rinting-press, and is applicable to fiat printing plates and also to curred printing plates, although portions of my invention are especially einploynhle in connection with curved printing plates.

it is the object of my invention. to bring all portions ot the printing, surface into the projection of the same surface, that is, into the same plane it the plate be a flat plate, and. into the same surface ot the sector of a cylinder it the plate be a curved plate, as determined by printing pressures further, to compress the backing of a printing; plate in order to impart to the same :1 great-er density than when the plate is :lirst lornied; further, to compress a printing plate for correction of its printing surface with pressure greater than the printing: pressure applied to the plate; further, to cause diiiercntial con'ipression of the backing of the printing plate according to the so idities ot the various portions of the printing surliace oi? the printing plate; further, to provide the diflercnt portions oi the printing plate with diiterent densities accordingto the solidities of the correspondlug; portions of the printing surface thereof; further, to compress the backing of a printinn plate with greater density at its solid printing portions than at its high-lighfor ligrhtcrprinling portions; further, to c0rroot a printing plate by pressing those porlions thereof which print with too light an impression toward the printing surface of the printing plate and then bringing, as by sharing, the various portions of the rear face ot the hacking into the projection of the some surlnce, that is, into the same plane in the case of a flat plate and into the same cylindrical projection in the case of a curved plate; .turther, to determine the correctness of the portions of the printing surface by means of a proof obtained by mounting the printing, pl lit-8 upon a substantially unyieldoble surface, for instance metal, and backi119; the proot sheet by a substantially unyieldnble surface, for instance metal, so as to obtain all portions of the proof between substantially unyielding surfaces which. throughout their areas are equidistant; further, to compress the backing of the'printin plate while confining said backing as a. whole in the plane of the plate; further, to compress the backing of a printing plate while maintaining the printing: lines in their original printing distance relations in the printing surface, further to compress the backing of a printing plate substantially immediately alter costing the some or before the metal thereot has acquired the hardening which it acquires by ltlJSG of days of time; further, to compress the backing of a printing plate in manner to avoid stretching of its printing surface; further, to compress a printing plate by pressures directed in a direction substantially perpendicular to the printing; surface of the printing plate and in manner to maintain the distances, parallel with the printing surface, between the printing lines; further, to press the sunken or concave printing portion of the printing surface located between printing edges into the plane of said printing edges; and, further, to reduce a printing plate to uniform thickness and different densities at its print ing portions.

It is the object of my invention, further, to press portions of the printing surface of a printing; plate which appear too light in the proving of the printing plate toward the projection ot the printing surface of the printing" plate and then reduce said pressed portions and the balance of the printing portions of the printing plate to a. uniform thickness, reproving the same, and again pressing the portions of said printing plate which appear too light, if any there be, toward the projection of the printing sur face of the plate, and reproving the same, in repeated seipiences, as determined by the proving thereof, routing out the portions-pf the plate in manner mentioned, if necessary or desirable. l have found in practice, however, that compression of a printing plate by vmy improved method is'ordinarily sutficient to render the printing surface thereof in substantially proper printing conditions, and that ordinarily little subsequent correction is required to render the plate properly printable.

I have found further, that when printing from plates as heretofore made. the printing surface of the plate will let down or the backing thereof compress in uneven manner away from the printing surface to cause imperiect printing. It is a further object of my invention, therefore, to compress the printing plate and especially the bacltinginaterial thereof to a density at least as great as any. density which might be imparted to the minting plate or its backing by printing pressures, especially at the solid portions of its printing areas.

It is the object of my invention. further, to roduce' an improved printing plate enibo in the characteristics and advanta es due to employment thereon of my improved method.

I have exemplified my invention as cinploying certain machinery and tools, although, it is obvious that these may be Wholly or partialiy dispensed with or changed or other machinery and tools em- .ployed within the spirit of my invention within the scopeof the appended claims.

' In the drawings:

Fig. 1 represents a plan view of: an ex:

emplifying painting plate.

on the line 22 of Fig. 1.

Fig. 3 represents a cross-section of a, por tion of the printing plate shown in Fig. 1, taken on the line 33 of Fig. 1, to illustrate the usual relations between the printing surface and the backing surface in their crude state, as in present methods, the plate being shown enlarged to disclose imperfections inherent in such plates.

I Fig. 4 is a cross-sectional View of the same plate, taken on the same section line as in F ig..3, the plate being shown subjected to compression by means of a compressing member, such as I prefer to employ, for compressing the printing plate.

Fig. 5 is a front elevation of an xernplt tying machine, partly broken away, for compressing the printing plate. 1

Fig. 6 is a plan vicw'oi one corner of the compressing member.

7 Fig.7 is a plan View of a portion of an exemplifying compressing member printing plates having a preponderance of printing portions.

F ig. 2 1S across-secmon of the sanietaken exemplifying compressing member having connected pressing faces.

Fig. 12 is a cross-section of the same, taken on the line 12-12 of Fig. 11.

Fig. 13 a plan View of the compressed backing of theprinting plate illustrated in Fig. 4-,: partly broken away.

' Fig. l l is .a vertical sectional view illustrating the shaving of the backing; of the printing plate while flat, illustrated as accomplished by an exemplified machine shown in longitudinal vertical section.

Fig. 15 is an end elevation of the same.

Fig. .16 is a vertical sectional view illustinting the proving of the printing plate while flat, the exemplifying machine there for being shown in longitudinal section.

Fig. 17 is a cross-sectional view illustrating' the curving of the printing plate.

Fig. 18 is a front elevation illustrating an exemplifying machine for compressing a curved printing plate.

Fig. 19 is a side elevation thereof.

F ig. 20 is a vertical cross-section oi. the same, taken on the line 20-2O of Fig. 19,

illustrating the compressing oi a curved V portions of the curved plate.

Fig. 26 is a cross-section of an exemplified device for trinnning theends oil the curved plateaiter its marginal bearer portions have been removed.

Fig. 27 is a vertical sectional view illustinting the proving of the curved printing plate, the exemplifying machine thereof be; ingr shown in longitudinal vertical section.

Fig. 28 is a cross-sectional'v-iew illustrat-.

ing the local correcting of the curved print- .ing plate. v

Fig. 29 is a vertical longitudinal section oi thesame, taken on the line 2929 of Fig. .28.

Fig. 39 is a view of a portion of th'e' backing of a curved printing plate having. the locally corrected portion therein.

Fig. 31 is a cross-sectional view illustrating the imposing of the curved printing plate on a convexly curved saddle.

printing plate, these views havin' indicat-- ing marks-in connection therewit to indicate their stralght axes or their curved axes.

Figs, 37, at, and 48 represent side eleva' tions of. the tools, Whose impressing faces are shown in Figs. 36, 43 and 3:7, respectively. q

Fig. 53 is a side elevation of a bluntpointed small impressing tool.

Fig. 54 is a side elevatioh of the small tool Whose impressing face is illustrated in Fig. 52; and

Fig. 55 is an end View of the same. It has heretofore been a-usual practice in making ready for the printing from printing plates, to overlay the tympan of the printing press on which the plates are to be printed at those portions at which the print ing appears too light in the proofs, or to underlay the printing plate at such portions,

or to both overlay and underlay at the insufiiciently printing portions, with the result that uneven surfaces are obtainedboth in the tympan and at the bottom of the printing plate, such system making it neces sary also to employ a comparatively soft tympan Other systems have attempted to produce the differences between solid and high-light printing efiect by locating the high-light printing portions of the plate lower than the solid portions, if a flat plate, or nearer the axis of the plate cylinder if a curved plate, this system also producing unevenness of printing surface. These uneven, waving or undulating surfaces at the rear face of the printing plate, or at the face of the tympan, or both, also, in the course of printing, or during a long run, vary from their original states, especially under the heavy print-pressures necessary to be can ployed-under such old methods, resulting in differences inappearance of the printing during different portions of the run and making subsequent make-readies necessary. I avoid all these ,ObjQUtlOnS by brlnging the printing surface of the printing lines and areas throughout the. printing plate equidistant from the rear or supporting surface of the printing plate, and bringing these two surfaces, respectively within the same projection'ofa given surface. I am enabled thereby to bring the backing or supporting surface and the printing lines into coaction with surfaces which are equidistant from each other and located in the same projections respectively of two spaced-apart surfaces, namely, the surface of the plate bed or plate cylinder ofthe printing press and'the surface of a coacting comparatively hard tympan sheet. I am thereby enabled to produce superior printing, and also to print with a tympanwhose impress surface is throughout substantially 'the'projeetion of the same surface, so that successive printings by difl'erent plates or printing .elements may be received by the same portions of the tympan, whereby my invention is especially adaptable for so-called wet printing, in which successive printings in diilerent colors are printed upon the same sheet during its single passage through the printing press, as Well, as to all other characters of printing, enhancingv the appearance and beauty of the printing and enabling me to reproduce the appearance of solids, highlights and intermediate printing el fects,in hi 'hl contrasted relations in the rinting t y P from coordinated plates representing dilierent colors, and avoiding the humps and hollows in the make-ready for one color which are detrimental to the make-ready for another color .in the old methods mentioned, and enhancing true registry of the printing lines.

My invention further enables printing to be accomplished with considerably lighter printing pressures and with harder tympans than under such older methods now in general use, and materially increases the num bers ofimprints which can be obtained from one make-ready of the printing subject. By my improved method, further, those portions of the printing plate subjected to pressures over the greater areas at the printing surface, namely, the solid "portions of the printing plate, are compressed to greater ex- .tent than the high-light or lighter printing portions of the plate, and printing plates are produced which retaln their clarity of printing efi'ect throughout long periods of use.

The distances and projections mentioned are intended tobe measured by print-pressures as they are ordinarily toorc'lined forobservation by the naked eye.

The printing plate is exemplified at 51-, and in the present exemplitication comprises a printing shell 52, which may be of usual electro-deposited metal, for instance, copper deposited on the matrix in elcctro-plating, and a backing onwhich the printing shell is fixedly supported, usually cast into the shell. This backing is usually a compo sition composed for example of lead, tin and antimony, in the proportion, for example, of ninety pounds of lead and five pounds each of: tin and uni/imam. it obvious however, that oaher hacking material may be employed and that. my invention is not limited. to printing; plates thus; formed.

in carrying oul my llll1)l0'\'i?(l method, the printing plate mar at i1s 111- be provided with lJQiUCIB 55, which nay desired be separated. "from ihe printing surfaeehy grooves 56, and he printing; plate may also have intermediate or interior hearers, on empliliecl at 57. T he mai-gii'ial hearers and intermediate hearers Ina he assooia as to make it advisable to merge the SElLlG, as shown at These hearers are useful for receiving the eoui iu-essive strains at the edges of the plates, anal in intermediate portions of the plate which would otherw' he devoid of support in the plane of the printlllg surface. These hearers are removed from. the plate in the course of; opcra'liioiji on the plate by my in'iprovecl method, as hereinafter explained, the marginal hearers being removed, as by sawing, and. the interior hearers being renmveil, as by routing, the latter operation lea ring spacer: in the of the plate free of priniinn' function. lily improved methoil is hewerei anpli'iyahle plai'es which. are not provieei. Willi hear I have in Fig. l shown an e eiuplilic: of the printing lace oi? a. prin 1. plaie be corrected, illumrating llic rlifi'eii we in solidifies otl" printing portions of a printing plate, and its hearers. fin iliis exemplilication the part SJ. represenl's a .oliil per-- lion, the parts 62 il).ll3lll'l6(il2ll' portionfi, and the parts 63 high-light portions oil the printing surface.

One of the charucl'ei's oE printing plates upon which my present inrontion ein ployahle, is shown, LlQ' iheil and claiineil in my Letters Patent .UU. lgilihlloil, iial'ell October 14, 1919, for method oi curring: printing plains and printing plates; curved thereby.

In my improved uielhoil, the priiilliug plate is either :iormeil oi? ag proxin'iate uniform tl'llClIHQF ri' .ucoil iherel'o, as hy approxnnatel (he same at as ..'pi'iiiting surface and shining the rear face thereof. The zl)l)i'() llllllll.(! sti'aig hl'eniug oi the printing surface may he accomplished by laying the printing plate prim ng face down on a substantially heavy ule'ial slal) having a plane iinpor-iing suriiace'znui pouiuh ing the hack of the printing" plai'e ihroug h the mel'linni of a usual inipoaing block and mallet.

The shaving may be accomplished v an usual means, and I have shown an i tire machine of this character in .31 and 15, in which repres nts the heel oi the machine, which heel is for instance Jf metal having a plane "face. A carriage ll its priutinp 66 thereon knife-sections 67, hetween which hearing rollers 68 are located to press the printing surface of H printing plate toward the heel. The carriage suitably driven, as by means of a pinion Tl ail-each side oi he carrim fixed. to a. shaft 72, joi maleo'. .i a beam I'll in. each siule of the frame i- I the n'iachiue, the pinions meshii 'a' rooiiheci racks on the respective si es m: the the carriage being guiileal in ite reoigrocaiiions in true lines by sui able guides Iii. liloreinent of the ear- .riage over the plate, iai'clpriniting face down upon the i')(.(l, causes shaving of the hacking face of ohe printing plate in spaced-apart paths, While the 'piai/e pressed toward the hell, die plate being then shifted to shave the ren'iaining portions of the mucking face, for reducing the printing plate to proximate uniform itliiel: between its printing lines and the hacking surface, but preferably thicker liian the inished )rinting plate to allow for *che con ion of the plate and l'o'r ei'ihsequeni; 51' Wings.

For more particular description of a shaving chine ei'n iiloyahie for the purp reference r aile to ihe shaving ina- (i and. claiineri in Leti'iltl, granted ine Deloand apparatus I plaice, ii; heiug, as- 111g machine harinp a haviu noveinent he eineraa and the print such C(JlMllhlOll is of UD iO density throughout, kiQ'ilSllJj of mg material being exipl'iiieil by elie unil or n spacing of the lines repr l "the croaaseclioni11g ol the plate ml 3. v l e pi'ii'itin plate is first formed, surface thatis to say, the printliues of ivhe printing Surface are wavy ii poi- 5h or the portions of the. printing not in he projeeiionss oi the .e, that. 1:5, in liha same plane if g plaie he a llaiv plate or the same 1. L a cylinder if the p .iniiing plate h iii-veil plaie. The rinizing plate, when Elm. icin'uul, or men induced to approxiiaale uniform thinness throughout at its printing linen I matter of fact and in printing effect undesirable irregularities n its printing surface and in thicknesses in ilQl'Cl portions of the plate, forming unue high or low places jhe p'i'inting surface, resulting in imperlecat printing i111.-

' :ssions and the practice heretofore of i" a ing the npan or nutierlaying the ill-3 lJ-lilkm on Wl'llCll the plate is mpro ie clwion oi the ame surface, and corres ioncling eripreeeions throughout .Ll,

blip

description and claims, arefio he under of the orlntinsr )laie ineouidi i .H l

siood as meaning the same plane of a flat surface, as applied to a plane surface, and the same curved surface of the sector of a). cylinder or cylindrical surface as applied to a curved surface. The term is employed for convenience, and avoids confusion in expression where it is desired to describe or claim both or either chnrnorers of surfaces.

In my improved nieiahocl, compress the backing of the )rinting plate, and solidify any so i or porous spoils in the plate, and press all portions of the printing surface of the printing plzu'ze fig-ward. e. giieu surface in order to locate ell pr ions of line printing surface in she projce on of the some surface, that is, in she same plane if the plate be a flat plate and info the same surface of a cylinder if "eheplaie be a curved plat-e.

The prinung pnil'e, especially the backing; materiel thereof, is in my improved method therefore next compressed, preferably selectivel according fo the solidifies of the portions o .the printing plate. portions 0.: the printing plale at the prin ingporfions thereof which are solid, are compressed to great-er. densities than hhose'porrions thereof which are previlcd with. higl'ilighiws or intermediate solidifies of printing; surface. These differences in densities are indicated in Fig. 4: by the differences in the closeness of rho cross-sectional lines. l accomplish this operation preferably by placing theprinting plate with its nrintiup; face upon a phone hard surface, preferably of ares than the area of the printing plate, es oi reslsrence member E30, which may be a steel sl b, (see Figs. 4; and 5), all portions of Will surface are in the some projecllion of a given. surface, and providing 21 compressing member, exemplified at 81, preferably o I aier urea i'hzin the area of the vpr-iuiinp' plate, which I apply to the backing surfece'ef the printing plate, this compressing member being provided with hard contact feces acting upon the backing .un't relations throughout from the hardened surface of the resistance member counting with the printing sru'fnce of the printing plate.

' Pressure applied to cause approach be tween snid compressing member and the co acting resisience nien'iber, lo compress the prinsl plate between said sin-faces so as "no cause sour" iession of luhe printing piste, these hard contsco feces preferably compressively oclt'mq noon the backing of the plaixe Whi l, in pn chine, is usually sofrer or more compre sible been th 2 ring; surface of materiel of the printihg plate. which is usual y u. printing shell. The printin surface 1., n uuy eveii'h supporir i by the no hardened surface the resistance niemher ol'lll crushing the eof or iniury ilUl'GtO,

"rho printing lines of t 2.2; located re-enfed as elevations 83, between which.

there are depressions Sal. These elevations preferably have sloping sidesfiii forming the walls of the depressions, thesidcs sloping away from each other at the respective elevations. for contracting: the depressions toward their bottoms, and the depressions are arranged to receive material of the buclc ing clue to the entrance into l-he backing of the elevations. The sloping sides of the depressions react upon the material received in the depressions to cause compressing; of those portions of the material of the backing received in said depressions. The slopin sides also nllord relief for permitting ready remo "ul of the compressing member after compression has taken place.

One of the objects of providing the raised compressing feces and cone-ting depressions is to permit the compressing faces to compressingly act on the backing mnferial throu hout the area of the some, and preferably to enter the bucking'nmterial for excrimp; the compression, thereby enhancing- "she compre YO effect by employment of less pressures, avoiding injury to the printing surface, and iireventing spreading of the printing plate in the direction of the plane of the plate, in order to maintain all printing; lines of the printing surface in o 'iginel relations in the directions of the plane of the plate to enable heir-dine registry between printing plates of s set of plates, especially useful in so-called multi-color Work.

A printing plate is in. practice, during the printing operation,- subjected to greater pressures per area, at the solid portions thereof, .than it is at the other portions thereof, for instance, the high-light portions of the same. I therefore provide the bucking of the printing plate at the sol-id portions thereof with greater density per area than the locking portions of the printing plufe at the other portions thereof for in stance the high-light portions. I

T he compression. may be accomplished by suit-able device capable of imparting substantially great pressures, for instance a. hydraulic press corrugiising, a bed 88, on which the resistance member is received and upon which latter the printing surface of, the printing plate is laid. (See Fig. 5). This resistance member is preferably a, herdened steel plate fo resist all compression by the printing plate and prevent injury to he printing plnlc. 1e compressing member provided with the compressing elevations and coacting depressions is placed upon the back 01 theprinting plate, so as to coact with the backing matorial of the printing plate. A plunger 89 of the press coacts with the bed thereof, its presser surface and bed surface being equidistant from each other throughout their areas, and the'movahle element, namely the plunger, being guided. as by guides 90, as is usual in a press of this character,' in true right lines perpendicular to such surfaces when applying the pressure. The applying of the pressure causes the compression of the printing plate in manner hereinhetore described, andusolidifies the same, including an soft or porous spots or portions therein.

li have shown the compressing elevations as having square areas. Other forms of compressing elevations may he employed, or the compressing elevations may be connected with each other for forming disconnected depressions hetweensaid ele *ations, for instance as shown in 11 and 12, in which the compressing elevations are exeinplified by the continuous elevated portions having the depressions 92 therein, and sloping walls 85.

I further prefer to employ compressing elevations of different areas and spacings according to-the average soliditics of the printing surface oi the printing plate to be compressed, and prefer that the greater the amount of solid areas there are in the printing plate, the greater shall he the proportion of compressing elevations in the compressing plate. Thus, as examples I have in 7 and 8 shown respectively a plan view and a cross-section of a portion of a compressing plate which I prefer to employ when operating upon printing plates having a large amount of solids in their printing; surfaces. Such plate may for instance have forty-live per cent of its area as elevation surface and fifty-five per cent of its area as depressions. The outer ends 86 of the elevations may he five thirtyseconds inch square and the sloping sides S5 have inclination of sixty degrees. In

Figs. 4; 5 and 6, l have excin'g'ililied respectively a cross-section and a plan view of a portion of a compressing n emher which I prefer to employ with a printing plate hav ing substantially balanced areas of solids and highlights or intermediate conditions oi solidities of printing: surfaces, on which the area of compressing surface may amount to twenty-five per cent and the areas of depression to seventy-tive per cent of the total area of the compressing memher; and the outer ends 86 of the elevations he one-eighth inch square, and the sloping sides have an inclination of sixty degrees. I have in 'Fig. 9 and 10 illustrated respectively a plan viewqand av cross section of an exemphned port-Ion of a compressing i'nemher,

assess;

which I prefer to employ for coacting with printing plates having a preponderance of high-lights, on which the areas of the compressing faces may be twelve per cent and of the depressions between the same eightycight per cent of the entire area of the compressing member. and the outer ends 86 of the elevations be three thirtpseconds inch square, and the sloping sides 85 have an inclination of sixty degrees All of the said elevations may have height of one-twentieth of an inch, ancl the bases of said sloping sides he spaced apart to provide the approximate areas mentioned. These examples are however exemplications and not limitations, as the areas, proportions of area and inclinations may vary within thespirit or" my invention.

Further instancing desirable pressures to he employed in my improved method. and

instcmcinp a printing plate comprising" an elcctroileposited copper shcll and a hacking composed of a cast hacking" metal, such as horcinhe'fore described, comprising lead. tin and antimony. it may he stated that l have found desirable pressures tor instance upon a printing plate having a substantially solid printing surface, and a sine ten inches by twelve inches. or one hundred and twenty square inches. to he a range of from one hundred and sixty tons to two luuidrcd tons for the entire plate. equalling a range of from substantially one and one-third tons per square inch of printing plate to one and two-thirds tons per square inch of printing plate; that. when compressing such printing plates of the given size having a. medium solidity of printing" surface, aggrogate pressures having a range of trom eight-y ill) - r tons to one hundred and sixty tons pressure may he rn'iployed. representing. pressures having a range of from two-thirds or a ton per square inch to suhslani ially one and onethird tons per square inch: and that when compressing said printing plates of such given having: a preponderance of light printing surface. aggregate pressures hav a range oi titty tons lo eighty tons may h employed. i-cprcsentin5; a. range of from live-twelill1s of a ton per square inch to twothirds o'l' a ton per square inch of printing platef it may he stated further, that in employingmy iu-m-overl method on printing plates in which me hacking material is Very hardy}: have found desirable pressures for instance upon a printing plate having a sub stantially solid printing surface and a size of ten inches by twelve inches or onev hundred and twenty square incl es, to he a ran e of from three hundred and fifty tons to SIX hundred tons "for the entire plate, equaling a range of from substantially three tons per square inch of printing; platelo five tons per square inch. of printing plate; that when compressing such printing plates of the given size having a medium solidity of printing surface, aggregate pressures having a range of from one hundred and fifty tons to three hundred and fifty tons pressure may he enuiloyed. reprcs sting pressures having a rangeoi from one and a fourth tons per square inch to substantially three tons per square inch; and that when compressing such printing plates of such given size having a preponderance ohhigh-liahts. aggregate pressures having a range of from fifty to one hundred and titty tons may be employed, representing a range of from substantially one-half to one and a quarter tons per square inch oliprinting plate. The medians ot the respective ranges of pressures printing plates than the printing; surfaces,

as at. 95. between such edges or boundaries. Exemplityinp this condition, I have found that. for instance, the dots in high-light areasl when subjected to highly magnified inspection, are really not dots, but, are inclosing circles, the inner aneas of which are sunken and either do not print or print very lightly, although to the naked eye they appear as fully developed dots.

By employment of my improvcdmethod, I am enabled to press the printing areas between boundary edges or lines into substantially the planes or projections of such printing boundaries or lines, so as to minimize the difference between such areas and said boui'ida ry edges or lines in'printinn for enhancing the printing elfcct. By means of my invention, I further bring all portions of the printing surface into the same projection of the same surface, so as to minimize the necessity for overlaying and underlying and producing highly eiiicient printint In subjecting the printing plate to. the

compressive actions hereinbefore described,

I produce greater densities in the solid portions of the printing plate than in the high light portions of the same. In the highlight portions of the printing plate there are greater areas in the printing face which are considerably depressed for avoiding printing thereof, and While allparts oi: the area oi? the printing plate are subjected to the same pressure in the coinpremive action upon the same, the pressures at the solid portions are resisted by greater areas of n tact between the printing surface and the coacting resistance plate. upon which'the same rests. than at the high-lightor lighter printing, portions of the printing plate, where greater imprinting areas are located. These upprinting areas permit. a portion of the metal been compressed to find relief in such imprinting areas. for causing less densities in the metal of the backing: of the plate at thoscpm'tions of the printing plate having more open areas. in their printing surface than the solid portions thereof, this relief of density varying according to the soliditics of the printing portions, the highlight portions being provided with the least densities.

Theselief of density mentioned is re ceived in the imprintingdepressions, which are in practice increased in depth, where necessary, as by routine O1'n0iJl1ElWlS8, in finishing the plate, but the distance of perpendicular yield of the bottoms of these depressions toward the printing sur'tace is slight. The distance ol reception of the compression faces into the plate may be instanced as one-tenth the thickness of the plate, although this distance may vary without departingfrom the spiritof my invention Within the scope of the appended claims. The compressive action upon the plates in my improved method is preterably greater than any compressive action on said plate by any pressures to which the printing plate is subjected in the printing operation to avoid compression of the printing plate during printing.

lVhcnprintiiu, from a plate made according' to my method, therefore, those portions or" the plate which are subjected to the greatest pressures per area in 1 the printing operations are resis ed by the greater densities in the printing plate, while those portions of the printing plate ivhiclraresubjected to the less pressures per aria in the printing operalion, "for instance, the higln light or lighter printing portions ot the printing plate, are resisted by the portions of the printing plate of less density, providing resistances in the printing plate proportional to the-printing pressures per area,

required for proper printing of the various printing portions of the plate. 7

it do not herein claim the means tor etlecting such pressures, having showngdescribed j and claimed the same in a copending appli'.

improvements in means for compressing printing; plates.

Nhen. the printing plants has been compressed, the leaching surface thereof Will.-

liave the form in the compressing face of the compressing member impressed the-rs; .Hl, :tor instance-forming ridges 53?. shown innier, the bed we burn em 109. A flexible steel band 110 mrrengeci. on the table and. receives a m 1.13- as Sheet 0i paper, thereon. printing; plate is laid printing face upon this sheet. 7 .ieeione 112, 113 are 'amranged to i; aheve the bed on hearers 11' Hi) the reends-1 of due 1'1i0hi. seeti0ne, for (1e- 0 1g the distance between the arc-fz1ces 10 therein, endieduce iii: which the meld-sections are pie. stzuitiniiy uniierm u hebireeli the bflh i201? plopeifly distancin printing POl'iiOEL) and I' l i I .3 from the bed. 0 accommodate hand, the cushion sheet and the in Figs. and 13. the printing plate to uniform thickness leetweeii its printing portions and T9111 porting face by remevin ridges; in the icizing instance by en '0 mei chine, hei'einhe shaving or shew J the same, to remo e the mi A light 1')" lQi "2mm ate. sieie of the machine is 3.5 mg phate so .A." he .1 m iih El teethed rack 11?, w th by pie Anemia 118 at each end of the "h, for causing; parallel the mel "eeiziens. The mohh ii iio. Li'Ci each other with 3 fm: roiling; the flexible 8d .0118 are 1T)" sub teuce r inst-zine ill iiilg' plate about the are mg; g: nd i 0 SUL'MOIB toward the n'nl'ldie lmieni 'iloi pi; ii-1., the mold-sections heciisc 25 be in the plate, suitable means a rack 103 and gear 1i side of the bed and. conceive movement between (her and rocked, and wohng; influence of the i'nehh 96 11/1151 miieh are hniiow and provided. with :1 coding liquid.

The mrempiiiied i'mrthod of curving: the printing; late is; fully shame and i'het i l 1 1 in" zuui-eezi Present 1Y0, 1318,967 zilsum! 0.6'18? 1011 w hm 1 the em ni m such method is not; closed by bhii; proof, me ri; phite 15 an eshentiui of the present method, and the placed face down uper "z correcting slab, for printing piate prechiced thereby, as other instanee ofnie'tnl, he i Lg; 21 tyne plane sun methods of em ipg the printing plate may face, those portions 01% "the hee humming the be employed. Without departing; f 'om the areas of the depre eion or (L "rit of my im'ention within the scope of priming suee hen-i A pgended eiaime. hack, and e L J; ihe printing plate has been curved, toward the plane hf: 1y again subjecked to e0i\'i 1ee-' ing' portions of Use 1 7 11 i1; its curved form, eheuhi it be he in tin same phzne A. any change in density or Chickhe =u1e0mphehmi by e"; the gnintiiig plate has taken place, inn if'iUl .ififii Led, ihe 11g epei'aiiien, 01 should, hath 'ng plate nee he in true which are hmYew-r .iiii ti l pi ue. emieentrie cyhiifinsi the pixie is to g. H the printing and (lOli'cifijin wi he COITLiWQSSiQH of 5311:? same may 111211 ii he-.ii'e '7 A 1 ce immediately 1111f]: the shaving 0i. 1ai ve umi'iiie M irintingpiute after 59 l )i;lil?-ilflifiiiig 1110:1111. ii in its [h i; sizute, 01' 11?) rind ii neuer' U ,"HQLQSSiOIl 0f the printing hereiimi" r i he dispensed with, and zi, c m'c we; ion {1 'ii'ed iinpzurimd in the "21mph 0!? J31 hie same i ii: been emvec i. nvd in my 18 be 2? inclusive, iiiusing machine by means ion of. curved printing In this QXGIIlPii-fififli, which ha ia sup- 122;, 101 rahly e'f grim er um L lick the 'iii ;.e area, of the printing; "pi te and mzwhine i i as (K Iipzi 111g ehzm. the printing face with fhieh it tenie 105, arranged 0 be unifmjmiy heziiefi .rziut, ewi ipi'e'iernhiy formeti en the by partially immersing the game in :i ineiizii i :(iei: having the dieni eter of havih 1.07, in ii'ieiii-ing' pee 108, heated. as by tile path 0?? rbhe priming surface of the prinh- Mm (iii ing plate while printing. The curved printing plate, represented at 125, is laid on this curved surface, with its printing face toward said surface. Pressure is applied for careing the printing surface to intimately contact or coact with this curved surface so as to locate the printing surface in the pro'irc tion of the sector of its proper cylinder.

The backing of the printing pl te then compressed, preferably on lines substantially perpendicular to the printing surface, or by pressures directed radially of said surface, and preferably in manner to maintain the distance relations, in the projection of the printingsurface, between the printing lines of said surface, in order to maintain the registry function of the printing plate. I have exemplified this as accomplished by means of compressing faces having coinpressing elevations 126, having sloping sides 85, and depressions 127, similar to the elevations 83 and depressions 8 t of the compressing member 81, exceut that in this case, the compressing n'ieinber. represented genorally at 128, is arranged on the sectors of a cylinder for coactinp witlithe curved surface at the back of the curved printing plate. v

p 1 ha ye shown these compressin elevations arranged on coin 'iressing plates lildsritably secured to compressing bodies 131, as

by a tongue and groove joint 13:3 between the same, or the compressing plateand its body may be formed as an'inte rral struc ture. The respective compressing plates and their respective bodies compose sectors of the compression member 128, which are arranged to be lnca'ed radially with relation tothe curved printing plate. In arrai'iginp; the compressing faces with relation. to the sectors of the compressing member, I prefer that the depressions between elevations be coincident with the lines of separations between the sectors.

in exemplification of means for causing" the compressing movement in y coin rise'a ram 135. moved in a guide 136, in a frame 137 of the machine. and having faces 1S8 thereon, arranged as sectors of frustro-- cones, which react with conipleinental wedge faces 139 on the sectors of the compressing member. Any suitable means may be proyided for operating the rain- I have shown the same as provided with a screw HQ, with which a nut lellis threaded, the not being shown as in the hub of a gear 142. The

nut is prevented from "moving endwise but is permitted to rotate. A pinion 143 meshes with the gear. The pinion is on a shaft 1-H journaled in bearings leo' on the frame, and having a hand-wheel 146 thereon for operating the same.

The sectors of the compressing member are provided with radially arranged guides 1 17, which are guided in guideways 14,8, 111

aprons 149, 150, of the machine frame, the sectors being guided in similar paths at their respective ends. The sectors may at that end thereof toward which the ram moves be provided with extensions 151 and additional guides 152 slidable in guideways 1:13v The respective sectors are at each end thereof provided with a lug 154, a spring 15s belwcensaid lug and a ledge 156 on the apron, normally urging the sector toward its operating part and normally urgingsepm ration between the coniprcssing member and the curved plate.

Means are provided for ready reception of the plate between the bed and the com pressing member, which is exemplified as accomplished by raising and lowering the bed, by means of guiding the bed in guides 158 in the frame. and providing eccentrics 159. fixed to shafts 160, journaled in bearings 161 of the frame, two of these shafts being shown. The eccentrics act on contact faces 15? or the bed. Arms 162 are fixed to the shafts. A. link 163 articulated at 16- with the arms, connect the arms for combined movements. Une ofthe arms may be extended as a handle ll lovenient of the bed toward the compression member ispreferably limited by stops 168 to locate the on red face of the bed at such point, so that re lies in the sector of the cylinder on which the plate ha-s been curved, or which is coincident with the desired cur-vat e "ofthe prii'iting plate, and to locatethis sector at such distance from the frustro-cones of the train, so that the axes of these frustrocones and said sector will be lfOlDC'lt'lGl'lt. This movement also preferably causes intimate contact between the rear face cf'the backing of the printing plate and the compressing" member, to arrange the printing plate a its true curvature.

'lhe radial movements of the sect. rs of the compressing n anber preferably then tale? place. Such movements are substantiall perpendicular to the various portions of the printing plate with which said sectors coact, ti coinpressiiiug face of said sec tors beingsuchconstruction to main ain the printing plate as Whole to its original dimensions and to maintain the distance relations in the projection of the printing Sl'll'fltCB, of the printing lines of said surface. as hereinbefore explained with relation to the compression of flat plates.

The action and results of compression and solidification of the curved plate are the same as heretofore explained in connection with the compression of flat plates. The portions of the'curved printin plate comprising; solid printing areas are compressed to greater density than the portions of the plate at which lighter printing surfaces are located. Compressing faces having various shapes and areas may also be employed in compressing curved plates as explained in relation to compressing fiat plates.

I do not herein claimthe'invention embraced in the machine herein shown and described for effecting compression'of -the curved printing plate, having shown, described and claimed said invention in a copending application filed by me in the U. S. Patent Oflice December 7, 1922, Serial No. (305,455, aforesaid.

It is obvious of course that other means may be employed for causing approach and recession between the curved ,printlng plate and a compression member, or for causing compression of the curved printing plate, within the spirit of my invention and the scope of the appended claims.

The rear face of the curved printing plate then has the undesirable ribs or projections 169 due to compression, removed, as by shaving.

The-sliaving of the inner face of the curved printi'n'gplate may be accomplished by laying the curvEPpIa-te in a suitable machine 1n a trough 170, (see Fig. 24) with" the printing face of the curved plate presented to the wall of the trough, and with one edge of the plate against the 10ngitu dinally e:;tendin, stop 171, and by passing -a rotary facing cutter 172 lengthwise of and parallel to its axis of rotation and to the axis of the plate across the inner face of the curved plate.

- line of the grooves 56 between said bearers and the printing surface, which may be accomplished by passing the same over a table 174 along a trimming saw 175. (See Fig. 25.)

The edge of the plate may then be provided with a suitable attaching face for setill curing the plate to the plate-cylinder, accomplished manually or by'n'iachine, as for instance by means of passing the same on a table 176 along the gage 177 and past a cutter 178 for shaping the edge of the plate, for instance, of bevel form, as shown at 179, (see Fig. 26), when it is desired to attach the plate to the plate cylinder by means of any suitable hook or registering devices.

When .the printing plate has been curved, compressed and shaved, it is preferably placed on a saddle 1810f hard metal, as of steel, having an imposing face 182 arranged on the sector of a cylinder substantially coincident with the sector of the cylinder on which the rear or inner face of the printing plate is formed. (See Figs. 31 and 32.) The printing plate is imposed toward the saddle, as by pounding by a mallet 183 upon an imposing block 181- having a concave imposing face 185, as of hard wood, arranged on the sector of a cylindercoincident with the sector of the cylinder on which the printing surface of the printing plate is formed. The imposing face impacts the printing surface of the printing plate, the blows of the mallet on the imposing block causing recession from the projection of the printing surface of any portions thereof backed by backing material which is still porous or which imparts improper support, which recession or yielding will be disclosed by the next proof by the light appearance in the proof of those yielded portions. The backing material at the yielded. portions is locally compressed by the tools hereinafter described to additionally solidify or compress this backing material.

lVhen the printingplate has been curved, compressed and shaved, and imposed, when the imposing of the printing plate is found desirable, a proof is taken of the same be tween hard surfaces, so as to disclose any imperfections in the printing surface, due, for instance, to any portion'or portions of the printing surface being below the projection of a given surface or below the same projection of a cylinder in which the portions of the printing surface properly placed are located. Such a proof may be obtained for instance by mounting the plate on a proof cylinder and printing a light proof therefrom upon a sheet laid upon a hard plate or sheet, for instance of metal, so as to cause the proof to be taken between hard surfaces which are equidistant, the printing plate having been suitably inked.

The proof may for instance be taken on a proof press comprising a metal plate cylinder 191, (see Fig. 27), to which the curved printing plate is suitably secured. and cansing coaction therebetween and a bed 192, as

by means of prm'iding each side of the bed with. a rack 193, and the plate cylinder with a gear 194 meshing therewith. The proof sheet 195 of paper is laid upon the bed, which is a plane surface,.or upon a hard sheet 196 preferably of metal of uniform thickness, the printing plate having been inked, coactive. movement is caused between the plate cylinder and the supporting bed for causing a light printing of the printing plate upon the proof sheet. r If such proof impression show any portion or portions of the printing plate as depressed or inside the projection of the cylinder on which the plate is formed, as by failure to print or printing too light in the proof, the curved printing plate is laid in ltit) iii) t emes a trough 200, with its printing surface upon the convexly curved hardened face of the trough, which is curved with a curvature coincident with. the curvature which the finished printing plate is to have, exemplitied for instance as a diameter of twelve and a halt inches, representing the diameter of the bearers oi a plate cylinder on which the printing plate is to he mounted. The co11- tact 10801 this trough for this printing surface, is preferably a hardened contact face, for instance or hardened steel. (See Figs. 28 and 29.}

That portion of the bucket" the printing plate which is opposite the depressed portion of the printing plate having been previously marked, this marked portion is then pressed tovard the curved face of the trough. This is accomplished by means of finishing tools, exemplified in Figs. 28 and 29, and Figs. 33 to inclusive, of the drawings. Thesev tools have impact faces 201 to 218, inclusive, for the back of the plate, arranged to depress the hollows in the printing surface oi. the printing plate into the projection of .said surface, and comprising for instance protuherances 223. having spaces between them. The areas of the impact faces of the protuberanccs vary in size according to the duties they are to perform. and. the areas they are to cover. They are shown substantiailp full-size in the drawings. The

impact faces are straight on one axis and curved on ti 2 axis at right angles thereto upon a curvature corresponding to the curvature of the inner face of the backing of the printing: plate being corrected. The in- (heating marh's22t indicate the direotions'in which the feces of the tools extend in straightlines, and the indicating marks 225 indicate the directions in which the impact faces thereof are curved.

The tools are provided with handles 227 by means of which they are gripped by the hand. The impact. of the tools upon the printing plate may be can d by suitable hammers. us at 228, prc'fe ably small and of little Weight, 'rlEPOUtllllQ' on the duties and forces or impacts which may he desired, for pressin the portion of the plate lacing corrected toward -c concave block or anvil, care being taken to avoid too great a depression. of the hacking material.

I do not herein claim the means for correcting printing 'ilates, embracing the small tools, saddle. anvil and coicting parts, having shown, described and claimed the same 1131M copcndinp; application, divisional heresift. filed by me in the United States Patent Uiiicc December T', 1 322, as Serial No. 605,4;54, for improvements in means for cor-- recting printing lhe backing of tife printingplate is then again shaved, in nihnncr hereinhefore e2ipiaiped, for again'reducing the corrected I to proximate uniform thickness'at the printing portions. The shaving thus removed usually represents a thickness of two thousandths of an inch upwards to usuallyahout live tl'iousandths of an inch. I

The printing plate thus corrected is again proved, and it any imperfections appear, the plate is again corrected in manner just described, and the hacking thereof again shaved, and these operations repeated in sequence .unt l the proving of the printing plate shows a printing plate Whose printing surfaces are throughout in the same cylindrical projection, and which at its printing portions is of uniform thickness, in printing effect, so as-to avoid or minimize the necessity of overlaying or underlaying in making ready the printing plate, and providing a printing plate which is substantiallyready for printing when properly placed upon the printing press. 7 i

The final shaving to which the curved plate has been subjected, is such as to reduce the curved plate to such thickness at its printing portions and such curvature at its inner or rear face, that the latter curvature will be coincident with the curvature of the plate-cylinder on which it is to be fastened for printing, and the printing surface be concm'itric therewith, in order that the inner or rear face of the printing plate will make intimate Contact throughout its area with the periphery of the plate cylinder, and the printingsurface be in printing relation throughout its printing area with the tympan, properly placed, of the printing press.-

If the printing plate is provided with. portions which must he removed from the printinc side prior to printing the plate, for instance, interior hearers, such removal is accomplishcd as by routingwvhen the proving of the printing plates shows a printing plate of uniform printable condition, Within the scope of my invention. After such re moval. or routing, the plate is referably again proved and any imperfection therein corrected in manner hereinbcfore described. The printing plate, Whether fiat or curved may be instai'iccd to he three-sixteenths of an inch thick in its finished state, but the dia1n- By means of my improved method. a

printing date obtained, having a print ingr surface. the printing lines of which are lociited in the surface of't'he same surface, that is the some planed? it be a straight 

